The Belmont Report's concept of justice means adolescents should participate in studies regarding sexually transmitted infections, given their high rates of infection. Yet they are also a vulnerable population, which means they should benefit from parental guidance without being inappropriately influenced in their decision-making. Understanding parent-adolescent discordance about willingness to participate (WTP) helps develop strategies to insure that both are comfortable with the final decision. Decision-making is influenced by developmental characteristics, thus, given the rapid changes during adolescence there will be changes over time. A safety trial of topical microbicides will be the context in which to examine WTP, allowing for applicability to other trial types. Specific Aims: 1) Describe the relationship between developmental characteristics (cognition and relevant experience, parenting and family variables) and WTP, attitudes towards privacy and parental influence, and discordance in the context of a study of STI prevention; 2) Describe the relationship between changes in developmental characteristics (cognition and relevant experience, parenting and family relationships) over time and WTP and attitudes towards privacy and parental influence, and discordance in WTP in the context of a study of STI prevention; 3) Describe adolescent-parent management of discordance as it relates to perceptions of the salient aspects of the trial and adolescent-parent interactional style as it relates to discordance and satisfaction with the final decision regarding participation. Methods: A multi-level strategy will be used to recruit 14-17 year old male and female adolescents and parents from primary care clinics. Data about non-participation will be obtained at all stages of decision-making in order to collect information about parents and adolescents who would normally not participate in research. The use of a hypothetical clinical trial allows for assessment of families who would not participate in trials. Parents and adolescents will be interviewed simultaneously by two different interviewers, and then complete a joint interview, which will be videotaped for coding of the interaction. To evaluate the impact of developmental change, participants will be re-interviewed one year later. Outcomes: This information will be used to develop and evaluate interventions designed to provide adolescents the opportunity to participate in studies with as much guidance as needed from parents and the autonomy to make their own decision.